Solenoid mechanism having two position latching means



1966 KlMlO HATASHlTA 3,235,777

SOLENOID MECHANISM HAVING TWO POSITION LATCHING MEANS Filed Aug. 23, 1963 United States Patent 3,235,777 SGLENOID MECHANHSM HAVING TWG POSITION LATCHING MEANS Kimio Hatashita, Gardena, Califi, assignor to Rocker Solenoid Company, Wilmington, Calif, a corporation of California Filed Aug. 23, 1963, Ser. No. 304,147 9 Claims. (Cl. 317-187) This invention relates to solenoid mechanisms and more particularly to a high precision spring-loaded twoposition latching solenoid operable to shift between alternate positions thereof with high reliability and accuracy by an initiating movement of unusually small magnitude.

Certain operating environments have need for impulse operated actuating mechanisms to move some control device with certaintly through a very small distance to an alternate position. It is desirable that the means provided be reliable to an unusually high degree and capable of operating for prolonged periods and through many cycles while sealed in a pressurized fluid atmosphere often of high magnitude. It is also desirable that the mechanism provided be capable of execution in miniature or subminiature embodiments and responsive to a small actuating force of predetermined value with full certainty that once moved from a prior position it will continue the movement until latching occurs in a precise alternate position.

Prior solenoid mechanisms evolved in efforts to meet these requirements fall far short of desired performance characteristics. One of themore satisfactory embodiments employs a garter spring circling the armature member and adapted to seat in one of two closely spaced annular grooves encircling the armature. However, one of the unsatisfactory limitations of this construction is its inherent limitation to a minimum actuating movement not less than the diameter of the garter spring employed. Attempts to reduce this diameter by making the spring it: self of smaller diameter are self-defeating because the spring then becomes too small to supply the requisite power, resiliency and reliability.

Other desirable attributes of a satisfactory solenoid mechanism include greater ruggedness, greater simplicity as respects the number and design of the components, and greater ease of assembly and disassembly.

To overcome the foregoing and other serious shortcomings of prior latching solenoid mechanisms there is provided by the present-invention an armature having a pair of V-shaped grooves and an associated latching mechanism including a sleeve provided with a shallow but wide inwardly facing groove. The width of this groove is slightly greater than the distance between the apexes of the V-grooves. Two sets of ball detents are provided, one for each of the grooves and normally held pressed against the opposite side walls of the inwardly facing groove by a'common coil spring. The ends of this spring bear against camming rings the flaring surfaces of which bear against the ball detents in a manner to urge the balls against the side walls of the groove and into seating engagement with the V-grooves. The armature and latching ring subassembly is adapted to be held detachably assembled within the receiving well of a solenoid coil by a retainer snap ring or the like and to be flooded with the high pressure fluid in operating environments having need for sealed pressurized operation of the mechanism.

It is therefore a primary object of the present invention to provide an improved, highly reliable, rugged, trouble-free latching solenoid mechanism.

Another object of the invention is the provision of a two-position latching armature subassembly responsive to a flux field to move it between its alternate positions and to hold it selectively but positively in either position until it is desired to move it to its alternate position.

Another object of the invention is the provision of a two-position armature subassembly designed for prolonged trouble-free operation within a pressurized sealed chamber and responsive to a flux field passed through the chamber walls to shift the mechanism between its alternate positions.

Another object of the invention is the provision of a solenoid actuating mechanism capable of construction in miniature and characterized by its ability to move some component through a predetermined distance of small magnitude with high precision and alacrity.

These and other more specific objects will appear upon reading the following specification and claims and upon considering in connection therewith the attached drawing to which they relate.

Referring now to the drawing in which a preferred embodiment of the invention is illustrated:

FIGURE 1 is a longitudinal sectional view on a greatly enlarged scale of an illustrative embodiment of the invention as applied to a sealed operating environment and showing the actuator latched in one of its two alternate positions;

FIGURE 2 is a fragmentary cross-sectional view taken along line 22 on FIGURE 1; and

FIGURE 3 is a fragmentary view similar to FIGURE 1 of the latching mechanism showing the parts in their alternate positions.

Referring more particularly to FIGURE 1, there is shown a typical embodiment of the solenoid mechanism incorporating the present invention and designated generally 10. The solenoid mechanism proper is shown operatively associated with a device to be controlled, such as a microswitch 11, suitably supported within a high pressure chamber 12 detachably secured to solenoid mechanism 10. It will be understood that the device operated may be a switch, valve, or other device of a great multitude of types required to be shifted between two definite predetermined positions. It will also be understood that the invention mechanism is equally suitable for use in subatmospheric operating conditions as well as in pressurized chambers subject to pressures of many thousands of pounds per square inch.

Solenoid 10 comprises a tubular spool 14 supporting a pair of electrical coils 15, 15 adjacent its opposite ends. This spool is formed of a plurality of members, the details of which will be described, all brazed, soldered, or welded together in a fluid-tight manner and include a flanged hub 16 at one end by which the solenoid can be detachably secured to chamber 12, as by bolts or any suitable fastener devices. All parts of spool 14 are of magnetic material except the two sleeve members 17, 17, these being of any suitable high-strength nonmagnetic material and offering a higher reluctance path for the flux than across the gap between the portions of the spool to either end thereof and armature 18 of magnetic material. The cylindrical outer protective housing 19 of the spool is likewise of magnetic material and is held assembled to the spool, as by the pin 20. To be noted is the fact that the spool has an annular flange 22 at its midportion providing a high efiiciency flux path for the flux between the adjacent ends of the two coils 15, 15. A slot 23 across this flange provides a channel for the coil terminals all of which, as here shown, extend from the spool through a bore 25 at one end of the spool.

The armature subassembly includes, as principal component, the armature proper 18, an elongated spindle-like extension 27 of nonmagnetic material and a flanged ring member 28 held loosely captive between shoulder 29 on extension 27 and the adjacent tapered end 30 of armature 18. As here shown, extension 27 is held assembled to armature 18 by thread 31 and may be locked against unthreading by a key 32.

The latching mechanism proper includes a pair of axially spaced V-shaped grooves 34, of identical construction adapted to seat a respective set of ball detents 36. Desirably there are enough balls in each set substantially to fill grooves 34 and 35 in the manner illustrated in FIG- URE 2. Only one set of ball detents can be seated at any given time. Preferably the grooves and sets of balls are so related that the other set is located directly on the edge of its seating groove in instant readiness to be rolled into seating engagement as the other set is rolled out of its groove.

The means for resiliently urging the balls into seating engagement comprise a pair of identical but oppositely facing shouldered camming rings 39 each having a 45 degree annular camming surface 40 hearing against a respective set of detent balls. A coil spring 42 encircling the shank of extension 27 has its ends seated in the shoulders of the camming rings and is effective to urge the ball sets against the opposite ends of the shallow but wide groove 43 opening inwardly into the bore extending through ring member 28.

From the foregoing it will be apparent that spring 42 is always effective through camming members 39 to hold the balls pressed aaginst the opposite side walls of annular groove 43, as well as toward seating engagement with one of the grooves 34, 35.

The armature subassembly just described is held detachably assembled within the central well of spool 14 in any suitable manner as by a split ring spring keeper 45 having its outer rim seating in a groove 46 of mounting hub 16. Release of this keeper enables the serviceman to grasp actuator extension 27 and withdraw the entire armature assembly from the inner end of spool 14. Reassembly is accomplished merely by inserting the armature subassembly into the spool until the flange at the outer end of ring member 28 is seated whereupon keeper 45 is inserted in groove 46.

To be observed from FIGURE 1 is the fact that the inner end 48 of armature 18 is tapered to nest within the complementally shaped bottom wall 49 of the spool. The operating tolerances between the OD. of armature 18 and the LD of the well are as small as feasible for maximum efiiciency of the flux path. Provision for the free fiow of fluid displaced by movement of the armature is provided by one or more channels 50 extending lengthwise of the armature with one end in communication with chamber 12 via an annular groove 51 in tapered end 30 of the armature and a passage 52 extending lengthwise of ring member 28.

The operation of the described typical embodiment of the invention will be quite apparent from the foregoing detailed description of its components and their functional and structural relationship to one another. In many installations, minimum actuating movement of the armature is a highly desirable prerequisite and this objective is easily realized by the present design. Thus the minimum actuating movement will be understood as approximately one-half the diameter of detent balls 36. Since it is easily feasible to use balls of miniature and subminiature size it will be appreciated that extremely small actuating movements are achievable.

Let it be assumed that the parts are in the position shown in FIGURE 1. Under these conditions both coils are de-energized and the armature and extension 27 are held latched in this position with certainty and assurance against movement due to shock, vibration or other hazard by the seating of the left-hand set of ball detents 36 in groove 34. They are held in this position by the action of spring 42 acting in concert with camming rings 39. The other set of ball detents is poised on the lefthand rim edge of the other seating groove 35 by the associated camming ring 39 in instant readiness to roll into groove 35 if a predetermined actuating force is applied and sufficient for groove 34 to shift the left-hand balls out of its groove. This is done by energizing the left-hand one of coils 15 providing a momentary highdensity flux field through the left-hand end of spool 14 and through armature 18 thereby causing it to shift to the left. As leftward movement starts, the right-hand inclined side of groove 34 cams balls 36 outward, forcing adjacent camming ring 39 to the right while compressing spring 42. This increased spring pressure is transmitted to the other camming ring thereby increasing the force acting on the right-hand set of balls urging them inwardly into groove 35 and aiding in the high-speed substantially instantaneous movement of the solenoid to its alternate position shown in FIGURE 3 with balls 36 fully seated in groove 35.

Return of the armature subassembly to its original position is accomplished equally, speedily and efficaciously by momentarily energizing the right-hand one of coils 15. The same action then occurs except in reverse relationship.

While the particular solenoid mechanism herein shown and disclosed in detail is fully capable of attaining the objects and providing the advantages hereinbefore stated, it is to be understood that it is merely illustrative of the presently preferred embodiments of the invention and that no limitations are intended to the details of construction or design herein shown other than as defined in the appended claims.

I claim:

1. A 2-position holding mechanism comprising a tubular housing member, an armature reciprocable axially of said housing member, a pair of annular V-shaped grooves encircling said armature and spaced apart axially thereof, a separate set of ball detents for each of said grooves, annular stop means encircling said armature opposite said grooves and spaced apart a distance slightly less than the distance between the remote sides of said grooves, spring pressed means urging said sets of ball detents against and toward seating engagement with the adjacent one of said grooves and cooperating with said grooves to hold said armature selectively in either of two positions with one set only of said balls seated in one of said grooves at any given time.

2. A 2-position holding mechanism as defined in claim 1 characterized in that said stops and said grooves are so related to said sets of ball detents that said armature automatically shifts into the alternate position thereof when moved an axial distance of approximately one-half the diameter of said ball detents.

3. A 2-position holding mechanism as defined in claim 1 characterized in that said spring means includes a pair of rings interposed between the ends of a coil spring and an associated set of said ball detents, said rings each having an outwardly flaring rim edge seating against said ball detents and disposed to urge said ball detents toward seating engagement in said grooves.

4. A solenoid operated control mechanism comprising a chamber adapted to be maintained sealed under internal pressure, a device therein operable between alternate positions, solenoid means housed partly within and partly without said chamber having an operating connection with said device, said solenoid means including a reciprocable armature movable through a short distance to operate said two-position device, means providing an annular chamber embracing and facing toward said armature, a pair of V-grooves encircling said armature and having the centers of their bottoms spaced apart an axial distance less than the distance between the opposed end walls of said annular chamber, a plurality of ball detents for each of said V-grooves, means including spring means urging said ball detents against an associated end wall of said annular chamber and toward seating engagement with said V-grooves, and electric coil means embracing said armature and operable when energized to shift said armature to-and-fro to operate said device between the respective alternate latching positions thereof.

5. A solenoid operated control mechanism as defined in claim 4 characterized in that said chamber is charged with fluid under superatmospheric pressure, and porting means between the opposite ends of said armature for the flow of said fluid between said opposite ends during shifting movement of said armature.

6. A solenoid operated control mechanism as defined in claim 5 characterized in the provision of spring detent means for holding said armature and said annular chamber means and the components housed therewithin assembled as a unit interiorly of said sealed chamber.

7. A two-position armature subassembly for use with a solenoid-operated mechanism, said subassembly comprising a cylindrical armature, an elongated shouldered extension detachably connected to one end of said armature, a ring member loosely journaled on said extension between said armature and the shoulder on said extension, said ring having a wide shallow annular groove facing toward said extension and having generally radial side walls, a pair of V-grooves encircling said extension and positioned adjacent a respective one of said radial side walls, two sets of ball detents held pressed against said radial side walls by spring coil means positioned between said sets of balls, and the distance between the apexes of said V-grooves being greater than the distance 6 between the centers of said two sets of balls by not less than one-half the ball diameters.

8. A subassembly as defined in claim 7 characterized in that said armature and said ring member are formed of magnetic material.

9. A subassembly as defined in claim 7 characterized in the provision of a pair of axially shiftable camming rings interposed one between each set of said ball detents and an associated end of said coil spring, said camming rings having oppositely diverging camming surfaces on their remotely spaced inner annular edges which camming surfaces bear against said ball surfaces and cooperating therewith in urging the balls into a respective one of said V-grooves.

References Cited by the Examiner UNITED STATES PATENTS 2,057,380 10/1936 Keefe. 2,632,425 3/ 1953 Grover. 3,040,217 6/ 1962 Conrad 317--191 X OTHER REFERENCES Schiebl: German Application No. 1,035,771, Pub. August 7, 1958.

BERNARD A. KILHEANY, Primary Examiner. JOHN F. BURNS, Examiner.

G. HARRIS, JR., Assistant Examiner. 

1. A 2-POSITION HOLDING MECHANISM COMPRISING A TUBULAR HOUSING MEMBER, AN ARMATURE RECIPROCABLE AXIALLY OF SAID HOUSING MEMBER, A PAIR OF ANNULAR V-SHAPED GROOVES ENCIRCLING SAID ARMATURE AND SPACED APART AXIALLY THEREOF, A SEPARATE SET OF BALL DETENTS FOR EACH OF SAID GROOVES, ANNULAR STOP MEANS ENCIRCLING SAID ARMATURE OPPOSITE SAID GROOVES AND SPACED APART A DISTANCE SLIGHTLY LESS THAN THE DISTANCE BETWEEN THE REMOTE SIDES OF SAID GROOVES SPRING PRESSED MEANS URGING SAID SETS OF BALL DETENTS AGAINST AND TOWARD SEATING ENGAGEMENT WITH THE ADJACENT ONE OF SAID GROOVES AND COOPERATING WITH SAID GROOVES TO HOLD SAID ARMATURE SELECTIVELY IN EITHER OF TWO POSITIONS WITH ONE SET ONLY OF SAID BALLS SEATED IN ONE OF SAID GROOVES AT ANY GIVEN TIME. 